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How we secretly introduced Haskell and got away with it

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Re: How we secretly introduced Haskell and got away with it

#161

Post by jacquesm »

_ao789 wrote: post #159
edblarney wrote: post #156

Earlier quoted context omitted.

Bingo. 1st iteration: 'does it' (barely) but kinda looks hacky 2cnd iteration: better. actually works. 3rd iteration: looks clean, concise, pro, something to be proud of! 3rd time is a charm in software. It's unbelievable how much clearer and more concise the code is 3rd time around. If you can ever actually get away with this on a project ... highly recommended.

I would love to have the opportunity to do this is my working life projects as most of the time while I'm doing iteration1, I have various others breathing down my neck about getting the next list of tasks in the sprint done as well. Time, and keeping others away is my hurdle.

The interesting thing is that in the longer term the third iteration will be the winner because it is more maintainable and most likely much easier to understand.

Re: How we secretly introduced Haskell and got away with it

#162

Post by jwatte »

Instead of using separate monad transformers, we use a single "World" that knows how to provide Redis, logging, iOS, and other typeclass instances.

There is a RealWorld that runs on top of IO and a FakeWorld that runs on top of pure State for unit testing.

This means that we have to wrap every single API into our own "SupportsRedis" and similar APIs, but in the end I think it's worth it! Unit tests are super fast and not intermittent at all.

Re: How we secretly introduced Haskell and got away with it

#163

Post by jwatte »

jacquesm wrote: post #161
_ao789 wrote: post #159

Earlier quoted context omitted.

I would love to have the opportunity to do this is my working life projects as most of the time while I'm doing iteration1, I have various others breathing down my neck about getting the next list of tasks in the sprint done as well. Time, and keeping others away is my hurdle.

The interesting thing is that in the longer term the third iteration will be the winner because it is more maintainable and most likely much easier to understand.

So, ship version one, early, and figure out whether it's worth keeping at all, or whether to kill it and not waste time on versions 2 and 3.

Re: How we secretly introduced Haskell and got away with it

#164

Post by jwatte »

darksaints wrote: post #90
cpeterso wrote: post #74

Earlier quoted context omitted.

It is interesting that Go and Rust eschewed OOP inheritance for simple encapsulation. Information hiding, not implementation inheritance, turned out to be the big practical benefit of OOP. Inheritance leads to fragile code because it allows unseen dependencies on private implementation details in far-flung classes and files. Many C++ game engines also moved away from huge class hierarchies of game objects to property…

There are many calls for, and proposals to include, some form of inheritance in Rust. Among other things, people have found that Rust is poorly suited to modeling HTML/XML hierarchies, retained mode GUIs, industrial simulations, code specialization, and some forms of video games. Inheritance is a missed feature. What is clear to me is that Rust does incredibly well without it, but wouldn't be hurt by having it. Most…

Aggregations and interfaces cover 99%of what you need. Implementation inheritance and virtual variation points create too tight coupling to be workable for evolving systems.

Re: How we secretly introduced Haskell and got away with it

#165

Post by jwatte »

pharrington wrote: post #97
Eridrus wrote: post #27

Earlier quoted context omitted.

It seems pretty easy to control for this, just write the functional version first, and if it is as big free your results obviously sidestep this criticism.

I'm not sure what you're getting at. He's saying Haskell's type safety makes impossible the bug that was in his JavaScript project. As far as I can tell, it's impossible to write a type safe system in pure JavaScript. edit: To clarify this thought a bit, obviously you can transpile code in a type safe language to JavaScript. At the abstraction level of the code written, the project is type safe. The generated JavaScr…

If Haskell is better than Python, then writing the first version in Haskell and the second version in Python should yield two versions that are closer in quality than if you did the reverse order. Assuming you can measure quality, this is a totally valid hypothesis to test!

Re: How we secretly introduced Haskell and got away with it

#167

Post by purescript »

chrisdone wrote: post #152
daxfohl wrote: post #38

I'm just starting with Haskell and PureScript. So far I'm liking the latter better. It solves a few of their gripes with respect to strings, laziness and records, plus has a more granular/extendable effects system and cleans up the standard typeclass hierarchy. Also `head []` doesn't crash. Of course Haskell is more mature, has support for multithreading and STM, compiles to native, so it's more performant. But PureS…

I think PureScript should catch on. The runtime performance story is much more predictable than Haskell, it integrates trivially with the most valuable target platform: JS, it has small output, fixes the warts of Haskell and yet is still pure. Aside from apps at work, I made some simple physics demos with it http://chrisdone.com/toys/ Perfomance seems good.

> Aside from apps at work

Now I'm curious :)

Re: How we secretly introduced Haskell and got away with it

#168

Post by saosebastiao »

jwatte wrote: post #164
darksaints wrote: post #90

Earlier quoted context omitted.

There are many calls for, and proposals to include, some form of inheritance in Rust. Among other things, people have found that Rust is poorly suited to modeling HTML/XML hierarchies, retained mode GUIs, industrial simulations, code specialization, and some forms of video games. Inheritance is a missed feature. What is clear to me is that Rust does incredibly well without it, but wouldn't be hurt by having it. Most…

Aggregations and interfaces cover 99%of what you need. Implementation inheritance and virtual variation points create too tight coupling to be workable for evolving systems.

Maybe 99% of what you need, but more like 70% of what I need. I'm not sure what you mean by aggregations, but I design industrial simulations relatively frequently and I've seen the suggestions for replacing inheritance with composed typeclasses and they are not even close to a true alternative. Rust's current troubles with GUI development would suggest the same pattern there too.

Re: How we secretly introduced Haskell and got away with it

#169

Post by pekk »

cmrdporcupine wrote: post #112
z3t4 wrote: post #29

Earlier quoted context omitted.

Articles like: We switched from language X to language Y with the conclusion that language Y is better smile My favorite is when they make another post half a year later saying they changed from Y to Z. It seems that following the trend and using the latest and greatest tools doesn't necessary mean the new tools are better, but that you got to rewrite your applications from scratch, with much more knowledge about the…

And they inevitably fail to mention the pissed-off product or QA manager or customer who realizes their favourite feature or corner case or bugfix is missing from the rewritten version because the developer didn't understand or notice that aspect of the original.

Instead of blaming the developers every time a feature is missing, consider who is setting the priorities for development. In places where developers are being paid for their work, this is rarely done by the developers themselves. Always interesting to see how much end users specifically blame developers for whatever's going on, I guess without understanding that there are usually all kinds of managers who may not understand software or the users or both but just want to sit on developers to crank features out as quickly as possible.

Re: How we secretly introduced Haskell and got away with it

#170

Post by pekk »

goatlover wrote: post #134
colorint wrote: post #79

Earlier quoted context omitted.

I think OOP will always run into the problem that it requires a taxonomical theory about your problem, which never holds up in reality. (This is just another way of saying, inheritance has to be a forest/bundle of disjoint trees. Yes, there's multiple inheritance, but I'm pretty sure acknowledging that is a mortal sin among OO types.) Haskell is slightly better, since typeclasses are less topologically constrained, b…

But then you end up growing your taxonomy ad-hoc. Also, Python does multiple inheritance sanely, and so does Eiffel.

Python might do nearly as well as any language could do with multiple inheritance, but "sanely" is relative, like finding the sanest way to drive two cars at once.
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